Controlled Attenuation Parameters for Steatosis Grading in Chronic Hepatitis C

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Controlled attenuation parameter diagnostic testing was externally validated against digital morphometry-quantified steatosis in patients with chronic hepatitis C.

The accuracy of controlled attenuation parameters (CAP) for steatosis grading in patients with chronic hepatitis C (CHC) was demonstrated to be strong compared with digital morphometric analysis, using liver biopsy fragments, according to a study published in the European Journal of Gastroenterology & Hepatology.1  

Histologic evaluation of liver biopsy fragments was previously considered to be the gold standard for fibrosis and steatosis staging; however, sampling and observer-related variability may hinder diagnostic performance.2-4 Recently, CAP has been developed in conjunction with vibration-controlled transient elastography (VCTE) and good performance has been observed, although differentiation between adjacent lower levels of steatosis can be challenging.5-8

Therefore, researchers in Brazil evaluated CAP diagnostic performance using digital morphometric quantification of steatosis on liver biopsy fragments as the gold standard in 312 patients with CHC.1 In addition, they investigated previously tested factors associated with accuracy, including variability and patient metabolic and biochemical characteristics as well as a newly described quality score for individual VCTE/CAP measurements.

They found that morphometry demonstrated no steatosis in 19.2% of patients, grade I steatosis in 28.5% of patients, grade II steatosis in 31.1% of patients, and grade III steatosis in 21.2% of patients. The use of CAP showed no steatosis in 11.2% of patients, grade I steatosis in 26.6% of patients, grade II steatosis in 56.7% of patients, and grade III steatosis in 5.4% of patients.

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Thus, there was a positive and independent correlation between CAP and morphometric analysis (P <.05), except in distinguishing grade I and grade II steatosis (P =.11). In addition, variability and higher liver stiffness were associated with lower performance. By achieving higher quality measurements, however, these limitations were overcome with excellent accuracy.

“In conclusion, CAP performance in comparison with the objective quantification of steatosis in [liver biopsy] through digital morphometric analysis was stronger than reported previously in this CHC population,” stated the authors.


  1. Mendes LC, Ferreira PA, Miotto N, et al. Controlled attenuation parameter for steatosis grading in chronic hepatitis C compared with digital morphometric analysis of liver biopsy: impact of individual elastography measurement quality [published online April 30, 2018]. Eur J Gastroenterol Hepatol. doi: 10.1097/MEG.0000000000001145
  2. Cholongitas E, Senzolo M, Standish R, et al. A systematic review of the quality of liver biopsy specimens. Am J Clin Pathol. 2006;125:710-721.
  3. Chindamo MC, Nunes-Pannain VL, Araújo-Neto JM, et al. Intermediate fibrosis staging in hepatitis C: a problem not overcome by optimal samples or pathologists’ expertise. Ann Hepatol. 2015;14:652-657.
  4. Poynard T, Lenaour G, Vaillant JC, et al. Liver biopsy analysis has a low level of performance for diagnosis of intermediate stages of fibrosis. Clin Gastroenterol Hepatol. 2012;10:657-663.
  5. Sasso M, Beaugrand M, de Ledinghen V, et al. Controlled attenuation parameter (CAP): a novel VCTE™ guided ultrasonic attenuation measurement for the evaluation of hepatic steatosis: preliminary study and validation in a cohort of patients with chronic liver disease from various causes. Ultrasound Med Biol. 2010;36:1825-1835.
  6. Karlas T, Petroff D, Sasso M, et al. Individual patient data meta-analysis of controlled attenuation parameter (CAP) technology for assessing steatosis. J Hepatol. 2017;66:1022-1030.
  7. Wang Y, Fan Q, Wang T, Wen J, Wang H, Zhang T. Controlled attenuation parameter for assessment of hepatic steatosis grades: a diagnostic meta-analysis. Int J Clin Exp Med. 2015; 8:17654-17663.
  8. Shi KQ, Tang JZ, Zhu XL, et al. Controlled attenuation parameter for the detection of steatosis severity in chronic liver disease: a meta-analysis of diagnostic accuracy. J Gastroenterol Hepatol. 2014;29:1149-1158.